that's to be expected at that age. Babies are babies doesn't matter what species. It's like asking a kitten, infant, or puppy to sit still for a long time. Occasionally they might do it, but don't expect it all the time. BDs are naturally inquisitive and it seems to be magnified when they're young. They tend to like to run around, explore and lick things.
Just keep at it, don't expect them to sit on your shoulder all night for a while. Just pet and snuggle them, then when they start getting antsy, give them some space to roam so they can get it out of their system or put them back in the habitat. You can block off areas you don't want them. When mine were hatchlings I used to restrict them to the couch.
I have a 6 month old. I can get her to sit on me for 30-60 minutes, depending on how tired she is. But after that, if she's still awake, she wanders off and there's no keeping her. She doesn't run off, but she is very persistent about where she wants to go. No amount of redirecting will work. She's always been rather calm though. My 5 month old on the other hand. After a little bit of squirming, we can get him to sit for about 10-15 minutes, then he's off.